Answer:
B
Step-by-step explanation:
Using Pythagoras' identity in the right triangle.
The square on the hypotenuse is equal to the sum of the squares on the other 2 sides, that is
x² + 30² = 50²
x² + 900 = 2500 ( subtract 900 from both sides )
x² = 1600 ( take the square root of both sides )
x = [tex]\sqrt{1600}[/tex] = 40 → B
